A machine apparatus that moves a subject to be moved is known; such machine apparatus is driven by a motor and the motor is controlled by a motor control apparatus. An example of the subject to be moved is a table. Specifically, the motor control apparatus receives, from a controller, a command signal that specifies a destination position of the table, receives, from a detector that detects a rotational position of the motor, a detection signal that indicates the rotational position, and controls the motor on the basis of the command signal and the detection signal, which are received.
To control the motor, the motor control apparatus calculates a value of voltage to be applied to the motor on the basis of the command signal and the detection signal. When calculating a value of the voltage, the motor control apparatus converts a value indicated by the command signal to a signal that indicates a rotational position of the motor, considering a gear ratio of gears included in the machine apparatus, a pitch of a ball screw included in the machine apparatus, and resolution of the detector. That is, the motor control apparatus performs unit conversion.
Patent Literature 1 discloses a method for fraction arithmetic in unit conversion, where the numerator and denominator both have an integer term and a power-of-two term. Patent Literature 2 discloses a technique for acquiring information that indicates resolution by communication. Patent Literature 3 discloses a technique for conversion from a position command of resolution of a controller to an internal position command of resolution higher than the resolution of a position detector.